Pbocess foe weighting natural silk



55 with organic acids.

Patented Feb. 27, 1934 PROCESS FOR WEIGHTING NATURAL SELK Rene Clavel, Basel, Switzerland No Drawing. Application July 10, 1931, Serial No. 550,950. in Germany January 2-9, 1931 12 Claims.

In order to produce a metal salt precipitate, e. g. tin phosphate, on natural silk for the purpose of weighting the same, the procedure has hitherto for some time been that the silk was 5 soaked with a weighting bath, e. g. with a solution of tin tetrachloride and thereupon subjected to a prolonged and thorough washing with water for the purpose of completely hydrolyzing the tin tetrachloride to tin hydroxide. The silk treated thus was then introduced into a fixing bath, e. g. a bath of sodium diphosphate, as a result of which tin phosphate is produced from the tin hydroxide.

The applicant has shown in prior specifications that the formation of tin hydroxide and conselll quently the time consuming washing process may be dispensed with if weighting baths or fixing baths are employed having a high acid concentration, or if the silk is subjected to a preliminary treatment with acids or acid salts, in other words,

if the weighting precipitate is produced directly from tin tetrachloride in presence of free acids instead of from tin hydroxide. By working in this way the silk may be directly passed from the metal salt bath, e. g. from a tin tetrachloride bath,

into the fixing bath, e. g. a phosphate bath, without Washing, acidification or neutralization. In many cases, however, the excess may be squeezed out.

The examples of procedure given in the prior applications show that especially for swelling organic acids can be used with advantage. However, while carrying out the above process on the technical scale, the observation has been made that the use of organic acids, such as for example, formic acid, aceti acid, monochlor-acetic acid, gives rise to troublesome secondary efiects, since these acids have an unfavorable influence on the person of the attendant Owing to their odor and their corrosive properties. Consequently, the weighting apparaus had to be wholly or partially closed and provided with ventilation.

By new experiments the applicant has also succeeded in using odorless and non-corrosive acids, such as, for example, hydrochloric acid, in such processes, it having been found that operations may then be carried out with open apparatus when treating the silk by the above characterized process. At the same time it was found that in the pre-treatment of the silk by swelling with an inorganic acid, preferably hydrochloric acid, the

process proceeds more rapidly and more thoroughly, but nevertheless the excess of acid mechanically taken up can be readily removed by a short washing operation, which is not the case Since hydrochloric acid is very cheap as compared with the organic acids previously employed, the use of this acid brings about a pronounced cheapening of the process as well. The hydrochloric acid may be mixed with protective colloids, such as, for example, albumin substances, in order to prevent any possible degradation of the silk.

ErampZa-A boiled, dried web of natural silk material is passed through commercial hydrychloric acid having a strength of about 26%, is washed on a conveyor belt, is subjected to suction, is unwound and then continually moved forwards and brought into contact successively with solutions of all or of a portion of the substances necessary for weighting silk. The tin baths used consist of tin tetrachloride of 30 Baum, the phosphate baths consist of 15% monosodium phosphate, which contain per litrelOU cc. of hydrochloric acid having a specific gravity of 1.16. After a brief washing operation and a squeezing operation, the material is subjected to a weighting with waterglass in a waterglass bath of at least 1 Baum at 50 C.

The formation of the weighting precipitate: from a solution of a salt of a metal in the presence of free hydrochloric acid may also occur in the presence of protective colloids. For example, the silk may be introduced into a concentrated solution of hydrochloric acid, which contains protective colloids and then in a bath of a salt of a metal to which no acid has been added, thereupon into a fixing bath, to which no acid has been added, and finally the silk may be washed. Instead of introducing the silk first into a solution of hydrochloric acid, it may also be introduced directly into a solution or" a salt of a metal, to which hydrochloric acid has been added and then treating it with a fixing bath to which no acid has been added, whereupon washing follows. The silk may be squeezed out between the bath of metallic salt and the fixing bath. Instead of using a bath of a metallic salt with hydrochloric acid added thereto and a fixing bath free from hydrochloric acid, the procedure may be the reverse, for example, such that the bath of metallic salt does not contain any added hydrochloric acid, but that the fixing bath does. Finally the bath of metallic salt, as well as the fixing bath, may both contain hydrochloric acid. In all cases, when desired, squeezing or wringing out may take place between the two baths. A solution of sodium phosphate which contains free hydrochloric acid may be used as a fixing bath in all the procedures noted.

What I claim is:

1. In a method for loading natural silk the steps of steeping the silk in a solution of a strong inorganic acid, treating the silk with a metal salt solution, treating the silk in a fixing bath, and washing the silk.

2. In a method for loading natural silk the steps of steeping the silk in a hydrogen chloride acid solution, treating the silk with a metal salt solution, treating the silk in a fixing bath, and washing the silk.

3. In a method for loading natural silk the steps of steeping the silk in a hydrogen chloride acid solution, treating the silk with a metal salt solution containing an addition of acid, treating the silk in a fixing bath, and Washing the silk.

4. In a method for the loading of natural silk the steps of steeping the silk in a hydrogen chloride acid solution, treating the silk with a metal salt solution, treating the silk with a fixing bath containing an addition of acid, and washing the silk.

5. A method according to claim 2 in which the metal salt solution and the fixing bath each contain an addition of acid.

6. In a method for loading natural silk, the steps of steeping the silk in a hydrogen chloride acid solution, Washing the silk with water, treating the silk with a metal salt solution, squeezing out excess of the solution, treating the silk in a fixing bath, squeezing out the excess of fixing bath, and washing the silk.

7. A method according to claim 6, in which the metal salt solution and the fixing bath each contain an addition of acid.

8. In a method for loading the natural silk, the steps of steeping the silk in a hydrogen chloride acid solution, Washing the silk with water, treating the silk with a metal salt solution, squeezing out the excess of the solution, treating the silk in a fixing bath containing an addition of acid, squeezing out the excess of the fixing bath, and Washing the silk.

9. In a method for loading natural silk, the steps of steeping the silk in a hydrogen chloride acid solution, Washing the silk With Water, treating the silk with a metal salt solution, squeezing out the excess of the solution, treating the silk in a fixing bath containing an addition of at least one acid salt, squeezing out the excess of the bath, and washing the silk.

10. In a method for loading natural silk, the steps of steeping the silk in a hydrogen chloride solution of approximately 26% 1-101 content, treating the silk in a metal salt solution, treating the silk in a fixing bath, and Washing the silk.

11. In a method for loading natural silk, the steps of steeping the silk in a solution of a strong inorganic acid containing protective colloids, treating the silk in a metal salt solution, treating the silk in a fixing bath, and Washing the silk.

12. In a method for loading natural silk, the steps of steeping the silk With a hydrogen chloride acid solution containing protective colloids, treating the silk with a metal salt solution, treating the silk with a fixing bath, and washing the silk.

RENE: CLAVEL. 

